The subject of this study is the politics of ethnic and racial relations in developing countries. It deals with a key aspect of population composition: the relation of ethnic composition to patterns of political participation and stability. There has been a growing awareness of the importance of ethnic relations in the politics of the new states. This awareness has not been matched by the development of a solid body of empirical theory. Because of the apparent multiethnic cohesion of nationalist movements and the ruling parties that assumed power at independence, social scientists were slow to appreciate the strength and significance of ethnic cleavages. In country after country, however, ethnic divisions have manifested themselves across a wide range of political and social activity--from educational, linguistic and economic policy to bureaucratic, military and party politics. Many divided societies have also experienced ethnically-related civil disturbances and, in several cases, wars of secession. The objective of this study, therefore, is to derive general propositions about the politics of ethnic relations from the concrete experience of ethnically-divided societies. The study centers on four major subject-areas: (1) the factors influencing the definition of ethnic group identity; (2) the sources of ethnic conflict; (3) the forms and patterns of ethnic politics; and (4) strategies of ethnic accommodation, focusing on the costs and benefits of alternative policies and techniques designed to reduce the level of ethnic conflict in divided societies. This last subdivision has rather clear relevance for policy, but the major thrust of the research is simply to identify and elaborate recurrent patterns of ethnic politics on a cross-cultural basis, building on untapped material already available in studies dealing with single countries or particular ethnic groups or movements.